Abstract: In this paper I examine the hypothesis that the frequency of rape is increased when another source of sex (prostitution) is limited or unavailable. To test this theory I regressed the rape rate in available OECD countries against a proxy for the availability of prostitution. The relationship was found to be anti-correlated at about the 90% confidence level. Using this model, it is estimated that if prostitution were legalized in the United States, the rape rate would decrease by roughly 25% for a decrease of approximately 25,000 rapes per year.

Introduction

In this paper I examine the hypothesis that rape is caused, at least in part, by the lack of other available sexual outlets. This could be at the time of the rape or due to attitudes created in the rapist earlier in life. This hypothesis is tested by regressing the rape rate in available Organization for Economic Cooperation and Development (OECD) countries against a proxy for the availability of sex through prostitution. OECD countries were picked in an attempt to minimize the economic differences between the countries in the sample. To measure the availability of prostitution in a given country, I divided the monthly per capita income by an estimate of the low-end price of a prostitute in a given country. The data for prostitution prices comes for the World Sex Guide, which includes data about prostitution prices reported by men who have hired prostitutes all over the world. The data for the homicide rate comes from the International Crime Statistics, the Statistical Abstracts of the United States, and The World Factbook of Criminal Justice Systems.

There are different theories as to why men rape. Researchers advocating the power thesis believe that the primary motivation leading to rape is the male desire to keep women in their place and to preserve sexual role inequality through violence. (Brownmiller) Other researchers have conducted surveys of rapists that indicate that lust was the primary motive for predatory rape. (Stevens) For a general discussion of these topics see a standard textbook such as Schmalleger, Criminal Justice. While this analysis does indicate that the availability of prostitution does decrease the frequency of rape, it does not necessarily distinguish between the two theories of motivation for rape. After all, a man could be paying a prostitute both to satisfy lust, and for the illusion of dominance over women.

Analysis

I regressed the rape rate in available OECD countries against both the availability of prostitution in a country and the homicide rate. To measure the availability of prostitution in a given country, I divided the monthly per capita income by an estimate of the low-end price of a prostitute in a given country. The one variable model gave the following equation:

R=12.0870  0.1070*I

where R is the rape rate per 100,000 people and I is the monthly income in units of prostitution encounters. The statistical significance of the constant is (t = 4.8384) and of I is (t = -1.7288) making this result significant beyond the 90% confidence level. I also did a multiple regression analysis of the rape rate against the homicide rate and the availability of sex through prostitution to try and remove a general propensity for violence in a country. The results follow:

R = 7.70795 + 1.4422*H  0.0935*I

where H is the homicide rate per 100,000 in the country. The constant has a t-stat of 1.7615, H has a t-stat of 1.17775 and I has a t-stat of 1.500 making I of borderline statistical significance at the 90% confidence level and the other variables not significant. The two independent variables are statistically independent with a t-stat of 0.8334.

Conclusion

There are, of course, many problems with this data. Rape is a crime that regularly goes unreported and what is considered rape in one countryís data set may not be considered rape in another countryís data set. The homicide rate also suffers from being defined differently in different countries  I have corrected for this problem to the best of my abilities by using multiple data sets. Given all of these problems, the analysis seems to support the hypothesis that the rape rate could be lowered if prostitution was more readily available. This would be accomplished in most countries by the legalization of prostitution. In the United States where prostitution is illegal, the low-end price for most prostitutes is about $200 and the monthly per capita income is $2,820. In Amsterdam, Netherlands where prostitution is legal the price is $30. If prostitution were legalized in the United States it is rational to assume that prices would resemble those in the Netherlands, this would result in a change in I of 80 and a decrease in the rape rate of 8.6 per 100,000. The population of the United States if roughly 300 million so this should result is a decrease of approximately 25,000 rapes per year.